Resealable packages are used in a number of fields. The packages may be designed in many different ways and may be either flexible or rigid. A very common solution to the problem of resealing the package is to provide a flap in the package wall whose delimitation corresponds to the desired opening. The delimitation consists of an indication, which may be an area of locally thinner material, a perforation or a through slit. The flap is then covered by an adhesive label which covers the whole flap and the indication. The indication, combined with the self-adhesive label, gives the package a controlled opening geometry and an opening that can be easily resealed by means of the label.
To guarantee the consumer that the package has not been opened, the label may be supplemented by a guarantee seal, usually in the form of a sticker, which is broken like a seal when the package is opened for the first time.
A typical flap and guarantee seal are disclosed in U.S. Pat. No. 4,874,096. The package is a ‘flow-pack’ and has an arcuate indication which defines the flap. The entire surface of the flap is covered by a resealable label. Further examples of documents describing this type of packages and labels are SE 463,666, EP 0,396,976, DE 4,241,423 and WO80/01157.
A common feature of the prior-art resealing labels mentioned above is that they cover the whole flap, which means, thus, that they are preferably rectangular, regardless of the shape of the indication. The rectangular shape is advantageous from the point of view of manufacture, since the labels are picked from a carrier in the form of a continuous, silicone-treated web and applied to the packages. On a continuous carrier, the gripping surface of the label is suitably oriented so that it faces the periphery of the carrier and thus follows the direction of feed of the carrier. This orientation allows ‘adhesive killing’, i e the operation used to make the gripping surface non-sticking, to be carried out while continuously feeding the carrier. A further advantage of the rectangular shape is that the amount of waste material is relatively small, since the entire width of the carrier can be used to form the label.
WO96/11147 discloses a package which is provided with an essentially V-shaped or arcuate slit in the packaging material. A label covers the slit and is releasably attached to the package on both sides of the slit to seal the package in a resealable manner. The label has two side edges, which extend on either side of the slit following generally the direction of the slit. The label has a gripping tab, which is not adhesively fixed to the package thereby enabling the user to grip it when opening the package. WO96/11147 further describes how such labels can be produced without any waste of material, the labels having a shape which allows them to bear directly against each other on a carrier in a label web. This prior-art solution may be efficient from the point of view of material utilization, but it is not optimal.